You may be thinking of solar to electric, and you are right. I'm thinking of a much simpler system, like a lifeboat emergency desalination unit writ large.
Solar evaporative works nicely.
Sorry, I was thinking of solar to electric as my thoughts for the thorium power plant were to produce electricity for the desalinization as well as for the grid.
But to your point, here is a wiki entry for vertical solar desalinization. Simple but effective.
The structure is a raised tower made of cement, with a tank at the top. The whole plant is covered with glass of the same shape, but slightly larger, allowing for a gap between the cement tower and the glass.
The tank is filled with saline water and water from an outside tank, drop by drop water enters the inner tank. The excessive water from the inner tank drips out onto the cement walls of the tower, from top to bottom. By solar radiation, the water on the wet surface and in the tank evaporate and condense on the inner surface of the glass cylinder and flow down onto the collecting drain channel. Meanwhile, the concentrated saline water drains out through a saline drain.
In this process fresh saline water is continuously added to the walls from the top of the tower. After evaporation, the remaining saline water falls down and drains out continuously. The movement of water also increases the energy of molecules and increases the evaporation process. The increase in the tower’s height also increases the production.
Whereas in the conventional system water that is filled remains at a standstill for several days, a condenser is provided at the top in an isolated space, allowing cold water is to pass through the condenser. The condensed hot vapors and hot water from the condenser are also thrown on the cement wall.
Different successive plants were constructed during 1960’s.
This plant’s base is 3.5 by 1.5 feet by 10 foot high, and gives about 12 liters of water per day.Built horizontally, a structured plant receives solar radiation at noon only. But Zuberi’s plant is a vertical tower and receives solar energy from sunrise till sunset. From early morning, it receives perpendicular radiation on one side of the plant. While at noon its top, gets radiation equivalent to the horizontal plant. From noon till sunset, the other side receives maximum radiation. By increasing the height, the tower plant receives more solar energy and the inner temperature increases as height increases. Ultimately this increases the water yield.
A number of experiments have been conducted and a much more productive plant has been developed, with further work continuing.
This project can be implemented anywhere there is ground water, brine or sea water available with suitable sun. During different experiments a plant six (6) 6 feet high can attain a temperature of 60 degrees Celsius, while a plant of ten (10) feet high can reach a temperature of up to 86 degree Celsius.